The present invention relates to wheelchairs having an improved and more versatile lateral frame construction.
Conventional wheelchairs or pushchairs may be of the fixed frame or folding frame types. A folding frame wheelchair or pushchair normally has left-hand and right-hand rigid closed frame structures interconnected by a transversely collapsible cross brace structure. The seat is normally carried on lateral rails which are secured to extensible guides supported on the lateral frames. In manually propelled wheelchairs there are provided large main wheels and relatively small front castors. The same arrangement may be present in pushchairs, or the pushchair may be provided with four relatively small fixed wheels e.g., for the transport of disabled airline passengers. In electrically powered wheelchairs, the main wheels are much smaller than the manually propelled main wheels, although they are still larger than the front castors.
Wheelchair patients vary in their requirements, and accordingly it is necessary to provide a range of different frame structures having different wheelbases, different widths, different back rest configurations, and different frame structures depending on whether the wheelchair is to be manually or electrically propelled or to be a pushchair. As a result, a wheelchair manufacturer has hitherto had to carry a large number of different parts, some of which may be required only relatively infrequently, so that the tooling cost involved has to be amortized over a relatively short production run.